B 76
[Subsidiary]
Diameter of reinforcements. L.N. 294/76.
Spacing of reinforcements. L.N. 294/76.
Shear reinforcement.
CAP. 123]
Building (Construction) Regulations
[1985 Ed.
123. (1) The diameter of a longitudinal reinforcement in a reinforced concrete column shall be not less than 12 mm.
(2) The diameter of the main reinforcement in a reinforced concrete slab shall be not less than 10 mm and that in a reinforced concrete beam not less than 12 mm.
(3) The diameter of a reinforcement in reinforced concrete (other than a longitudinal reinforcement in a column or a main reinforcement in a beam or slab) and the diameter of a link, helix, stirrup or the like, shall be not less than 6 mm.
(4) The diameter of reinforcement forming a fabric reinforcement for the purpose of resisting tension in reinforced concrete shall be not less than 5 mm.
124. (1) The distance between 2 reinforcements in reinforced concrete shall be not less than-
(a) the diameter of either bar if their diameters are equal;
(b) the diameter of the larger bar if their diameters are unequal; or
(c) 5 mm more than the greatest size of coarse aggregate comprised in the concrete,
whichever is the greatest dimension.
(2) (a) When immersion vibrators are used, sufficient space shall be provided to enable the vibrator to be inserted.
(b) The vertical distance between 2 horizontal main reinforcements and the corresponding distance at right angles to 2 inclined main reinforcements shall be not less than 15 mm or the maximum size of the coarse aggregate, whichever is the greater.
(3) The provisions of paragraph (1) shall not apply at a splice, except for the distance between pairs of lapped bars, nor to bars transverse to one another.
(4) The pitch of main reinforcements in a reinforced concrete solid slab shall not be more than 3 times the effective depth of that slab.
(5) The pitch of distributing reinforcements in a reinforced concrete solid slab shall be not more than 4 times the effective depth of that slab.
125. (1) Where at any cross-section the shear stress, as calculated from the equation given in regulation 140(1), exceeds the maximum permissible shear stress specified in regulation 116, the whole shearing force shall be provided for by the tensile resistance of shear reinforcement acting in proper combination with the compressive resistance in the concrete: